If you do something you enjoy – such as winning a game or eating a tasty meal – you feel good. In the world of neuroscience this is known as ‘reward’, and it’s triggered by nerve cells (neurons) in the brain that release a chemical called dopamine. This fires up other nerve cells and reinforces the idea that you enjoy the thing you’re doing and want to do it again. In contrast, unpleasant activities shut down dopamine-releasing neurons and lead to avoidance. Human brains are complicated, so scientists are studying the simpler desires of fruit flies, whose dopamine neurons fire in response to sugary water. This image shows a fruit fly’s brain under the microscope, with a particular group of dopamine neurons highlighted in green. By tracing the signals that go in and out of these cells, scientists can start to understand how patterns of nerve cell activation lead to specific behaviours.
Written by Kat Arney
BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences (the new name for the MRC Clinical Sciences Centre) the website aims to engage everyone, young and old, in the wonders of biomedicine. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.